This invention relates to reaction products of an epoxide and a polyalkylenepolyamine and to methods for preparing the same.
Polymers derived from a polyalkylenepolyamine and epoxide are known to be excellent weak base ion exchange resins. See, for example, Ion Exchange, by F. Helfferich, published in 1962 by McGraw-Hill Book Company, New York. The preparation of these polymers in granular form is well known in the art. See, for example, U.S. Pat. No. 2,469,683 to Dudley and Lundberg wherein an anion active resin is prepared by reacting an alkylene polyamine with a monoepoxide, e.g., epihalohydrin, in water and optionally a small amount of NaOH. The resulting gelled mass of polymer is then ground for use. Similarly, a method for preparing granules of an alkylene polyamine and polyepoxide, i.e., an organic compound containing a plurality of oxiranyl groups is disclosed in U.S. Pat. No. 2,469,684 to Dudley.
In many applications, particularly continuous operations, such resins are advantageously prepared in the form of spheroidal beads. A method for preparing spheroidal weak base ion exchange resin particles of a polyalkylenepolyamine and a monoepoxide is disclosed in U.S. Pat. Nos. 2,614,085 and 2,610,156 to Lundberg wherein an aqueous syrup of a resinous partial condensation product of the polyalkylenepolyamine and monoepoxide is dispersed with mechanical agitation in an organic, non-solvent medium containing a surface active agent. The resulting partially condensed dispersed globules are converted to a water-insoluble resin upon heating. Unfortunately, the beads prepared by this method are of irregular shape and of generally non-uniform sizes. Moreover, the agitation rate used in such a method must be carefully controlled to prevent excessive agglomeration. Furthermore, this method which requires substantial expenditures of time, energy, material and apparatus is not easily practiced in a continuous manner. Finally, spheroidal beads of a polyalkylenepolyamine and polyepoxide cannot be prepared by this method.
Improvements of the aforementioned method are disclosed in U.S. Pat. Nos. 3,005,786 to Greer and 3,725,313 to Naumann, Schon, Schnoring and Pampus. U.S. Pat. No. 3,005,786 teaches using a dispersing agent of chlorinated rubber, chlorosulfonated polyethylene or polyvinylchloride in the organic non-solvent. U.S. Pat. No. 3,725,313 discloses the use of a rubber-like homopolymer or copolymer of a conjugated diolefin or a cycloalkenamers as the dispersing agent in the organic non-solvent. Use of the dispersing agents disclosed in these patents reduces the agglomeration of the beads during cure and provides for a more uniform bead size. Unfortunately, the other stated deficiencies of the aforementioned method of Lundberg are not substantially reduced.
In view of the stated deficiencies of the prior art, it remains highly desirable to provide an improved method for preparing the reaction product of a polyalkylenepolyamine and an epoxide in the form of beads. Moreover, it is particularly desirable to provide a method for making beads of polyalkylenepolyamine/polyepoxide reaction products which have not been prepared heretofore.